Furnace



Aug. 7. 1928. 1,679,724

- G. P. 'JACKSON ET AL FURNAC AFiled Sept.17, 1924 2 Sheets-Sheet 2 (74994 l E ATORNEYS 'Patented Aug. 7, 192e.

. QUNITED STATES PATENT oFFicE.

GEORGE P. JACKSON, OF FLUSHING, AND HARLOW D. SAVAGE, F SCARSDALE, NE/W i YORK, ASSIGNORS T0 COMBUSTION ENGINEERING CORPORATION, OF NEW YORK,

N. Y., A CORPORATION OF NEW YORK.

runNAcE.

Application filed September 17, 1924. Serial No. '288,132.

`In vthe drawings, Fig. 1 shows a vertical i ll section through a steam boiler furnace embodying our -invention. Fig. 2 shows a'horizontal section, taken as indicated by the line 2--2 in Fig. 1.

. Fig. 3 is a fragmentary view similar to l yim Fig. 1, but illustrating a somewhatl d ierent arrangement or construction.

Fig. 4 shows. a fragmentary horizontal section through the furnace wall, illustrat-l ing still another difference in construction. A As shown in Fig. 1, the combustion cham ber proper atl 10 is a large, deep, `unobstructed chamber. Powdered fuelpreferably with somewhatmore than carrying air'is fed in through one or more downward directed 30 burners 14 mounted in the roof l5 lnear the front wall 16, and is continually ignited by the heat of the latter and ofthe furnace Air additional to that entering at the burner 14 is `(or may be) supplied through inlet 35. `openingsl? at various heightsA in the front wall 16, so as to afford suilicient air to assure combustion, and to form, lif desired, a cooling zone in thebottom region 18. of the 'chamber ,10. The burning streamv 4(of minj' 40 gled air, powdered fuel, combustible gases f from the fuel, and products of combustion) descends in the front of the chamber V1() until its momentum is overcome by thel upward draft through the boiler. It .then bends rearward and ascends, and finally leaves the combustion chamber 10 throughan 'outlet 19v about as indicated the arrows. 'The 'size of the chamber 10 and the contiguity ofthe unbaled downward and upward uel streams y and their 'change ofdirection-as described assure rapid an complete combustion inthe chamber 10; and, as a result, very high tem We have hereinafter de.

encounters and passes t Eeratures indeed are developed.v ;(Here and ereinafter, I use the. terms frontl and rear in reference to the regions where 'the furnace 1s fired and whence the products of combustion make thelr exit from its main l combustion space or chamber 10, respectively.)

The relatively heav1 incombustiblel residue from the .fuel fa ls or is precipitated toward the Hoor and toward the sides of the chamber 10, in a finely divided and molten condition. That falling directly to the floor rough a coolingzone 1n vits lower region 18, maintained either by an excess of air admitted .asr'already described, or by a water screen consisting of a bank 0f inclined tubes 30 which extend across the combustion 4chamber 10,-.-or by."

both. Inv the coolin zone at 18 `(however it'be maintained), t e refuse particles are` cooled below fusion temperature, so that they collect 1n the hopper1ike furnace lbottom as a dust, which can easily be dumped .out or otherwise removed at a clean-out.

opening 33. The iater screen 3() alsoV absorbs radiant heat from the deposit'in the bottom of the furnace and prevents refusion thereof by such heat Vfrom above.

As here shown, the rear portionl of the combustion chamber 10-or, at least, of the, combustion space proper above the screen 30'-is definedby heat absorbent surfaces `of steam generating elements'34 consisting of water tubes with `lo ngitudinal absorbent fins or flanges at either slde. These tubes 34 are arranged Awithl their iinsoverlapping slightl so as to form, ine'ifect, a-complete heat a sorbent metallic wall varound three sides" of the rear portion of the combustionl spacer-with the exce tion 'of small areas at the rearcorners. utsideof them is a refractory, thermo-insulative wall 35., At the sidesof .the combustion chamberlO the tubes 34 extendV forward to about the front edge ofthejoutlet 19, which .approximately coincides with vthe rear ofthe descending fuel stream inythe front of thecombustion chamber. In front Ojf bustion chamberl is4 definedA 'lient"reverberatory wallsof the refractory and thermo-insulativej construction 'for vpowdered'fuel,

` The.. i@ will-fl. i#

A.under the inuence of the heat radiated -andrefieeted from these highly reverberav tory walls at the front and .sides of the front portion of the combustion chamber vuntil after ignition has taken place, .com-

bustion has become thoroughly established, and ample air has been admitted at the openings 17 (and become suiiicientl heated) to aure its completion. Only afterthis has occurred' is theV fuel stream exposed, as it bends rearward and ascends, to the absorptive action of the tubes 34 surrounding the rear portion of the chamber 10. These tubes 34 not only absorb the heat by conduction from the outer skin or envelope of the now voluminous fuel stream rising amongst them,` but also vabsorb a large amount of radiant-heat from the mass of the flaming stream. At this Vstage, however, the combustion is so thoroughly established that this loss of heat does not prevent its completion by the time vthe gases ass into the outlet 19. The cooling effect of t e tubes 34 lis suilicient to revent an adhesion of refuse from the fue to the tu or to the narrow areas of refractory walls at the rear corners of the chamber 10; ,on the contrary, all suchpar` ticles striking the tubes bounce oi and fall through the coolingzone at to the hopperlike furnace. bottom. i Y Y As here shown, provision is made for reheating the air for combustion in there ractory walled front portion of the combustion chamber 10. For this urpose, this portion of controlling of the -wall is built dou le, with extra wide refractory courses 36 extending across the.

interspace to form horizontal ducts 37. Air admitted through damier controlled openin@ 38 at the rear. en s of these ducts 37,

in the side walls, passes forward through them and across the front of the furnace, and is admitted to the combustion chamber through the aforementioned openings 17.

` though not suiciently to interferewith igni` tion and combustion as already described.

AsshowninFigS.1,2,thetubes34at the `rear and at the sid of the combustionchamber 10 are bent outwardthrough the refractory wall behind them and connected in the lower and upper headers 41, 42.

screen tubes 30 are connected into the headers 43 at their lower front ends andl into headers 44. at their rear upper ends; and these headers -44 Vare connected at- 45 to the superjacent headers 41 belonging to the tubes 34 on theY rear furnace wall. The

front header 43 is connected -at. 43al to the side headers 41, and may be connected by down-flow vpipes 45 to a header 46 it- 'self connected at. 47 to the down-Bow headers 48 4of a .water tube boiler overlying the combustion chamber outlet 19, while all the headers 42 may be connected by up-flow pipes 49 to the water spaces of the boiler at its up-low end,-here .proper are shown.

. In the construction shown in Fig. 3, the lower headers 41 for the side tubes 34 have a separate downtake' connection 55, and the tubes 30 curve upward at their rear and are connected direct-ly. into the header 41 belongingto the rear tubes 34.

As shown in Fig. 4, the horizontal air duets 37 may, if desired, open rearward at 58, instead of opening laterally through the outer shell of the double wall as in Figs. 1, 2, and 3.

We claim:

A pulverized fuel combustion chamber having a row of substantially upright closely spaced exposed water tubes forming the rear wall, asimilar rowforming a portion of each side wall, a sheathing forsaidrows of tubes, exposed refractori'es forming the front wall and the remaining portion of each side wall,

.a plurality of substantially horizontal verti cally spaced air passages in said refractory iront and side walls,.inlets to said passages in the side walls adjacent the yportion of the chamber formed by the water tubes and outy lets from said passages into the chamber in vthe front wall., means for admitting fuel adjacent the said refractories to be burned in space in the chamber. and an outlet from the chamber Vfor the gaseous products of combustion.

In testimony whereof, we have hereunto signed our names.

GEORGE P. JACKSON.

HARLOW D. SAVAGE.v 

